Acute disseminated encephalomyelitis (ADEM) is an immune-mediated inflammatory demyelization disorder of the central nervous system. The white matter of the brain and spinal cord is predominantly affected although cortical gray matter, thalamus, and basal ganglia are often involved. A 24-year-old female presented with complaints of headache, instability and with a sixth cranial nerve paresis following an upper respiratory disease. Multiple rings like contrast enhanced lesions were seen on magnetic resonance imaging (MRI) and the diagnosis was confirmed by a brain biopsy as ADEM. The patient's complaints ceased and MRI lesions regressed after 1000mg methylprednisolone administration. Brain biopsy is rarely needed to diagnose ADEM and to exclude other infectious or malign processes. An experienced radiologist can usually make a diagnosis of ADEM correctly and during the follow-up period after medical treatment the resolution of MRI abnormalities in serial MRI scanning can also play a supportive role in diagnosing ADEM.